Pump Arrangements & Redundancy

Pump arrangement determines how many pumps are installed and how they operate. The choice affects capital cost, reliability, maintenance flexibility, and energy efficiency. Plumbing Booster supports common arrangements and recommends the appropriate configuration based on system type and criticality.

**Single pump**: One pump handles the entire duty. Lowest cost, no redundancy. Suitable for non-critical applications with easy replacement access. **Duty/Standby (N+1)**: Two pumps, one operating and one standby. If the duty pump fails, the standby takes over. Standard for most building applications requiring reliability. **Multiple pumps in parallel (duty/assist)**: Two or more pumps share the flow. Each pump handles a portion of the total duty. Better efficiency at part-load conditions. Used for variable demand systems. **Duplex/Triplex**: Common for sewage and sump applications. Two (duplex) or three (triplex) pumps alternate duty, extending pump life. ASPE recommends same-capacity pumps for lift stations.

N+1 means providing one more pump than needed to meet the design duty. If N pumps can handle the design flow, N+1 pumps are installed. This ensures the system can meet full demand even if one pump fails. Example: If 1 pump at 50 GPM meets the design flow, install 2 pumps (1+1). Each pump is sized for 100% of the duty. In normal operation, one runs and one stands by. If the duty pump fails, the standby starts automatically. For larger systems: If 2 pumps at 50 GPM each are needed for 100 GPM, install 3 pumps (2+1). Each pump handles 50 GPM, and any 2 can meet the 100 GPM requirement.

In the Pumps module, select the pump arrangement per system. The software: - Calculates per-pump duty for multi-pump arrangements - Generates per-duty-pump system curves - Recommends duplex/triplex for sewage lift stations when ASPE review is enabled - Shows total installed capacity vs design requirement - Validates that the selected arrangement can meet design flow with one pump out of service (for N+1)